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Calculation of XANES/ELNES Spectra of All Edges in Si 3 N 4 and Si 2 N 2 O
Author(s) -
Ching WaiYim,
Mo ShangDi,
Chen Yu
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00030.x
Subject(s) - xanes , spectral line , atomic physics , chemistry , ground state , analytical chemistry (journal) , crystallography , materials science , molecular physics , physics , chromatography , astronomy
Using a recently developed first‐principles supercell method that includes the electron and core‐hole interaction, the XANES/ELNES spectra of Si‐ L 2,3 , Si‐ K , and N‐ K edges in α‐Si 3 N 4 , β‐Si 3 N 4 , spinel c ‐Si 3 N 4 , and Si 2 N 2 O were calculated and compared. The difference in total energies between the initial ground state and the final core‐hole state provides the transition energy. The calculated spectra are found to be in good agreement with the experimental measurements on β‐Si 3 N 4 and c ‐Si 3 N 4 . The differences in the XANES/ELNES spectra for the same element in different crystals are explained in terms of differences in local bonding. The use of orbital‐decomposed local density of states to explain the measured spectra is shown to be inadequate. These results reaffirm the importance of including the core‐hole effect in any XANES/ELNES spectral calculation.